The Duke of Buccleuch has been accused of breaking Scotland's 'right to roam' law by trying to make people pay to take walks on his 1,000-acre estate near Edinburgh.

The UK's largest private landowner is charging dog walkers £20 for an "annual pass" and demanding £1 from ramblers and cyclists when they visit Dalkeith Country Park. He is also installing CCTV, electric controls on the main gate, and attempting to restrict access at other entrances.

The duke's moves have infuriated residents, ramblers and politicians who argue that local people have been walking in the park for free for decades. Some say the charges are "extortionate" and "totally unreasonable", with some walkers refusing to pay them.

But the Buccleuch estate is "mystified" by "misleading" suggestions that it is trying to restrict access. New security measures were being introduced to prevent anti-social behaviour and the killing of deer but these should not deter walkers, it says.

Dalkeith Country Park is one of Buccleuch's five major country estates, four of them in Scotland and one in England, covering a total of over 240,000 acres. It is the site of Dalkeith Palace, built in 1702 and used by Bonnie Prince Charlie during the Jacobite Rebellion in 1745.

The park is currently undergoing a £4 million redevelopment, including a café, shops and an adventure playground. Close to the Edinburgh bypass, it has long been a popular day out in the country for people from in and around the city.

But Buccleuch's attempts to charge for and control access have now run into fierce opposition. Jim Mitchell, a dog owner from Dalkeith, has been walking several times a week in the park for the last 30 years without being charged.

"Now I'm being stopped and asked to pay extortionate amounts just to walk my dog. I think it's totally unreasonable and it really sickens me," he told the Sunday Herald.

"I don't think we should be charged. Under the land reform legislation, we're perfectly entitled to walk there."

John Ritchie, a dog owner from Newtongrange who regularly uses the park, said: "There are lots of people and locals that refuse to pay. The gullible and the tourists are the ones being fleeced."

Dave Morris, the former director of Ramblers Scotland, accused the duke of taking a "hostile attitude" to public access. He was breaching land reform law by ignoring the free use of Dalkeith park by local people over many years, he argued.

"He needs to abandon his charging plans or face legislative action in the Scottish courts to secure public rights of access. The best way for him to have due regard to his access responsibilities is for him to charge only for car parking."

Ramblers Scotland had received many queries from the public concerned about charging and access at the park, reported policy manager, Helen Todd. "It's disappointing that the estate has a less than welcoming attitude to its neighbours," she said.

According to Colin Beattie, the SNP MSP for Midlothian North and Musselburgh, the fact that local people had been walking for free in the park for years meant that their access was protected by the 'right to roam' law as long as they were well behaved. "I would be appalled if the landowner felt he had the right to impose charges and to restrict entry," he said.

East Lothian Council, which covers part of Dalkeith park, implied that there was an issue over access. "The council is working with Buccleuch to see if the aspirations of the estate can be met while at the same time asserting free right of access from Old Craighall for walkers, riders and cyclists," said a council spokeswoman.

Midlothian Council, however, suggested that Buccleuch might be complying with land reform legislation because the estate had previously charged for access in the summer months between about 10am and 4pm. Most residents knew they could walk for free outwith those times, the council said.

Dalkeith Country Park's manager, Edward Morris, insisted that access to the park had been encouraged for generations. "There has been a nominal charge for access for several decades and people have always visited the park in great numbers," he said.

"Our plans to alter the structure of our access fee have been well publicised and have been formulated following extensive consultation with local residents, community councils and stakeholders."

The park's redevelopment coincided with a problem of anti-social behaviour at certain times of day. "This has included incidents of deer being attacked and killed and other forms of unacceptable disorder," Morris said.

"As a result, we are having to install a number of new security measures including CCTV. There is no question of these measures deterring walkers or access takers who are welcome and are encouraged to visit our estates."

Buccleuch remained committed to offering the "widest possible access" whilst ensuring the safety and enjoyment of all, he added. "This includes local residents and dog walkers who value the park so highly and have been supportive of our plans."